#include <iostream>
using namespace std;

class Human{
public:
    int age;
    constexpr Human(int age) : age(age) {}
};


constexpr double doubleSum(double a, double b)
{
    return a+b;
}


void Human_test1()
{
    constexpr Human human1(1);
    // human1.age ++;
    cout << human1.age << endl;
    cout << doubleSum(10,12) << endl;
}